This invention relates to a sealing means for sealing a terminal section extending between a terminal member of a sealed type storage battery and an inner peripheral surface of an annular member disposed to surround the terminal member.
A known means for sealing a terminal section of a sealed alkaline storage battery such as used under vacuum atmosphere, for instance, for an artificial satellite or the like, comprises a terminal member and an annular ceramic member disposed to surround the terminal member, hermetically sealed together, as shown in FIG. 1. Namely, because the terminal member a is required to be hermetically sealed to a metallic battery cover b in electrically insulating relation therewith, there is interposed therebetween hermetically an annular ceramic member c sealed as described below. Namely, the terminal member a and the inner peripheral surface of the annular ceramic member c are bonded together hermetically through a single continuous band-shaped annular bonding material layer of a desired thickness. Namely, the layer comprises an annular metallized bonding material layer d formed by metallizing the ceramic member c, an annular plating layer e formed on the inner peripheral surface of the layer d, e.g., by a nickel plating procedure, and an annular soldering layer f bonding between the plating layer e and the peripheral surface of the terminal member a by a soldering procedure.
Almost the same hermetically sealing as above is applied between an outer peripheral surface of the annular ceramic member c and an opening member b' of the cover b surrounding the same, but any further explanation thereof is omitted for convenience.
The resultant ceramic type sealed storage battery terminal section provided with such a sealing means is defective in that, in the course of use of the battery, the metal of the nickel plating layer e and that of the metallized layer d are corroded, and the metallized layer d allows the electrolyte to pass therethrough owing to its ceramic porosity, and accordingly it often happens that the electrolyte gradually creeps upwards and leaks out to the outside surface of the battery and consequently the battery is lowered in function and is shortened in its service life. Thus, as long as the terminal section is sealed by a continuous layer as shown in FIG. 1, there occurs the unfavorable phenomenon that the electrolyte is liable to leak outside along the layer.